Filter equipment for removing particulate and undesirable gaseous components from gas streams have been in existence for many years. Odors, organic gases and particulate removal are frequently the primary concern when the gas stream to be cleaned is an air stream and especially when the air is intended to be vented to the environment.
An example of such equipment for use over a hospital bed for a recuperating patient is disclosed in U.S. Pat. No. 3,935,803. In this invention hospital room air is filtered in a canopy-like apparatus and the filter air is showered down over the hospital bed. In the apparatus air is prefiltered and passed through replaceable activated charcoal filters.
A larger filter for use in a commercial food cooking operation disclosed in U.S. Pat. No. 4,350,504. This patent discloses several designs with charcoal bed elements arranged in a series of permanently installed V-shaped configurations. The charcoal is reactivated in place with a built-in heater and damper assembly. Since the filter system is designed mainly for a hood over a stove in a restaurant, the reactivation cycle can take place after normal restaurant business hours without interruption to food preparation operations.
A multistage pollution control system with an inverted conical shaped lower bed-first stage and an upright conical shaped upper bed-second stage is disclosed in NTIS report, PB-221 138 entitled Package Sorption Device System Study. A pelletized carbon is added to the upper bed and spent pellets removed through a valve in the lower bed.
A housing containing a combination evaporative cooler and carbon filter is disclosed in U.S. Pat. No. 3,086,342 which has a pair of carbon filters pivotally mounted in the housing. Other filtering systems which may contain shaped filters are disclosed in U.S. Pat. No. 3,824,770 for removing bacteria from air, and U.S. Pat. No. 4,344,778 for adsorbing moisture from air.
The principal disadvantages of these and many other similar prior art filter systems are that they are either poorly suited for use in filtering large volumes of gases, or, if they are useful for filtering large volumes of air, either the space such systems require or the ease of replacement of spent filter media particles is difficult and time consuming.
Replaceable cartridges or filter elements containing a adsorbent particle media usually require a relatively long period of time for replacing and resealing in filtration systems. The principal advantage of replaceable cartridges resides in the ability to reactivated them by heating or other means.
Systems which reactivate the spent adsorbent particle media without removal from the system during a separate regeneration cycle, require the system to be inoperative during the regeneration cycle.
What is needed therefore is a filtering system which can handle a large volume of gas, including a gas such as air, when such gases have objectionable gaseous contaminates by adsorbing such gaseous contaminates with a adsorbent. What is also needed is a system in which spent adsorbent particles can be quickly removed and replaced with fresh adsorbent media. Therefore what is needed is a large filtration system wherein the adsorbent particles can be quickly discharged and recharged without substantial loss of on-stream time. The arrangement of the containment housing for the adsorbent particles should be such that the adsorbent particles will not form bridges during charging of the adsorbent into its housing and also such that uniform filter bed densities can be quickly achieved and duplicated from one adsorbent charging to the next. There is also needed a system in which spent particle filter or adsorbent media can be quickly removed without appreciable time spent in breaking up bridged material and scraping of the walls of the container or housing to dislodge and remove filter particles or adsorbent.